pub fn dp_rec_mc(amount: u32) -> u32 {
    let coins = [100, 50, 30, 20, 10, 5, 2, 1];
    let mut account_mut = amount;
    let mut nums = 0;
    for i in 0..coins.len() {
        if coins[i] <= amount {
            nums += account_mut / coins[i];
            account_mut %= coins[i];
        }
    }
    return nums;
}
